The Islamic State beheaded 15 of its own fighters after a bout of infighting in Afghanistan’s eastern province of Nangarhar.
Nangarhar, on the porous border with Pakistan, has become a stronghold for Islamic State, generally known as Daesh in Afghanistan and the killings occurred in the Surkh Ab bazaar of Achin district.
IS has grown to become one of the country’s most dangerous militant groups since it appeared around the start of 2015.
Further details were not available and there was no confirmation from Islamic State, whose local branch is known as Islamic State in Khorasan, an old name for the area that includes modern Afghanistan.
The Taliban and Islamic State have frequently fought each other in Nangarhar and both have been targeted by sustained U.S. air strikes.
But the exact nature of the relationship between the two groups is little understood. There have been isolated incidents in Afghanistan in which the fighters of both appear to have cooperated.
Afghan intelligence documents that emerged this year showed security officials believe Islamic State is present in nine provinces, from Nangarhar and Kunar in the east to Jawzjan, Faryab and Badakhshan in the north and Ghor in the central west.
Meanwhile in a separate suicide attack on Thursday tore into a crowd in the provincial capital, Jalalabad, killing at least eight.
The suicide bomber blew himself up at a meeting of supporters of a police commander who was sacked for illegal land grabbing.
There was no claim of responsibility and no immediate indication of who was behind the attack on the crowd, which had gathered to demand the reinstatement of the commander, who survived the attack.
A spokesman for the Jalalabad hospital confirmed eight people had been killed and 15 wounded.